<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<style>
			#div1{
				width: 200px;
				height: 200px;
				background: red;
				float: left;
			}
			#div2{
				width: 300px;
				height: 300px;
				background: yellow;
				float: left;
				
			}
			#div3{
				width: 300px;
				height: 300px;
				background: black;
				float: left;
				
			}
		</style>
	</head>
	<body>
		<div id="noteDiv">
			<div id="div1"></div>
			<div id="div2"></div>
		</div>
		<script>
			var odiv = document.createElement('div');
			odiv.id = 'div3';
			noteDiv.insertBefore(odiv,div1)
		</script>
	</body>
</html>